Two-dimensional mirror symmetry from M-theory

We construct two-dimensional gauge theories with N=(4,4) supersymmetry from branes of type IIA string theory. Quantum effects in the two-dimensional gauge theory are analyzed by embedding the IIA brane construction into M-theory. We find that the Coulomb branch of one theory and the Higgs branch of a mirror theory become equivalent at strong coupling. A relationship to the decoupling limit of the type IIA and IIB 5-branes in matrix theory is shown. T-duality between the ALE metric and the wormhole metric of Callan, Harvey, and Strominger is discussed from a brane perspective and some puzzles regarding string duality resolved. We comment on the existence of a quantum Higgs branch in two-dimensional theories. Branes prove to be useful tools in analyzing singular conformal field theories. (orig.)